[Immunology of tuberculosis].

Protective immunity against Mycobacterium tuberculosis is mediated by specific T lymphocytes and executed by mononuclear phagocytes. The crosstalk between distinct T cell subsets and macrophages involves various cytokines. Attraction of blood monocytes to the site of mycobacterial replication and local macrophage activation result in granuloma formation. Interactions between T cell subsets and macrophages within granulomas enable the host to restrict mycobacterial growth, but only rarely cause sterile eradication. Therefore, at later time points, active tuberculosis may develop as a consequence of weakened immunity.